DA6240C.007

17 October, 2016

1 (13)

MAS6240C

Piezo Driver with Multi-Mode Charge Pump

 Both Single Ended and

Differential Output

 Three-Step Volume Adjusting

 Up to 18Vpp Output from 3V

Supply

 One Wire Audio & Shutdown

Control

 High Efficiency

 Solution without Inductors

 Low External Part Count

DESCRIPTION

MAS6240 is a piezo driver device that can drive

outputs up to 18Vpp from 3V supply. An internal three-

mode charge pump generates boosted supply voltage

for piezo driver. For adjusting the piezo element sound

volume, the charge pump can operate in either of a

1x, 2x or 3x mode. In 1x mode the output voltage is

same to the input voltage, in 2x or 3x mode the input

voltage is boosted up accordingly 2 or 3 times. Charge

pump mode is selected by control pins EN1 and EN2

(see Table 2 on page 3).

MAS6240 is an easy and low-cost solution for piezo

driver, since only 4 small value capacitors are needed

in addition to sound element - the use of inductors can

be avoided. The inductorless design also causes

significantly less disturbance to the surrounding

circuits making it an ideal choice for sensitive designs.

Its charge pump switches at 1MHz, allowing to using

as small as 100nF external capacitors.

Control logic is switching the charge pump on at first

rising signal of digital input (DIN) pin. The piezo driver

is enabled at a second rising edge of a pulse at DIN

and the signal is transferred to piezo output VO1. The

same signal is inverted into output VO2 for using

differential output. The charge pump and piezo driver

disable signal will be generated while the signal at DIN

has been at low mostly for 50ms. When disabled the

piezo driver outputs VO1 and VO2 are pulled actively

to GND.

Continuous logic high level at DIN input causes the

charge pump to be turned ON but leaves the piezo

driver disabled. In that state the VOUT charge pump

output of the MAS6240C2 version can be used to

power the external LED or any other external circuit up

to 5mA load. The output voltage is still selectable at

three steps.

In "disabled" mode (DIN has been low for 15ms

typically) all functional blocks are switched off to

achieve the quiescent current less than 1μA.

Two QFN packaged device versions are available. C1

version has short circuit protection which limits input

current taken from the supplies. It is suitable for

driving piezo in single ended configuration. C2 version

does not have input current limitation but it provides

maximum output current drive capability and loudest

sound pressure level. It is suited for driving piezo in

both single ended and differential configurations. In

the die form version D1 the input current limitation is

selectable by bonding.

FEATURES

APPLICATIONS

Piezo Driver & Charge Pump

 Thin QFN 2x2 and 3x3 12ld packages

 Three-Step Volume Adjusting

 Both Single Ended and Differential Output

 Up to 18Vpp Output from 3V Supply

 One Wire Audio & Shutdown Control

 Low External Part Count

 Inductorless low EMI solution

 Wrist Watches

 Alarm Clocks

 Handheld GPS devices

 PDAs

 Portable Device with Sound Feature

 1 MHz Switching Frequency

 Multi-Mode Charge Pump (1x/2x/3x)